A topic of endless banter, I predict. Well, it's already known to be--so not much of a prediction there. The answer is no; not that particular brand; but yes, I have used other types. My experience is that they can work reasonably well up to a point. But in the end--at best--they only shorten the duration of some rocking episodes and dampen, somewhat, the amplitude of those episodes. Shorter duration, lower amplitude at the low intensity end of the range of rocking/rolling episodes. I'm speaking here in terms of fairly small waves/wavelets as drivers. Something big comes along and the "stoppers" can do little; actually, next to nothing to tap it down in short time.
I deploy on one side only from my spinnaker pole set athwart and supported outboard by the spinnaker halyard. It is set high enough that I can walk or run under it. The stopper is suspended from the pole by a floating (polypropylene) line led through a snatch block attached to the pole and then stopped off at the cockpit via a second snatch block to a deck padeye. I can adjust the depth of the stopper by easing or trimming that line. I send the device down about 10-12 ft in the hope that it will not pop out and strike the boat on a really big roll. When I push or pull the pole forward the stopper is automatically hoisted to deck level or nearly, so I can fetch it aboard w/o lifting it much myself. So, it's very fast to recover, even at night.
The stopper itself is a rectangle welded of black iron made of two frames, painted, with a zig-zag pattern of cross members on one frame. A layer of thick plastic cut from the center out to form flappers shaped like pie slices is sandwiched between the two frames which are then fastened together. As it goes down, the water passes though the flappers, pushing them up some; as it comes up the water presses the plastic against the cross members of the lower frame, sealing the flappers, etc. A four-point bridle of wire rope from the corners to a brass ring is used to suspend it. I've used the Davidson (Mexican hat) cones as well.
Way too much trouble, IMHO; and not even a bit more effective than the DYI device described.
Very similar to the one pictured below.